1. Field of the Invention
The present invention relates to drywall finish trim devices typically utilized in finishing a drywall installation at a corner or terminus.
2. Description of the Prior Art
Drywall, sometimes also referred to as wallboard, is a staple in the construction industry as an economical alternative to joint compound for forming the interior walls and ceilings of rooms in residential, commercial, and industrial buildings. The materials used in drywall construction include gypsum board, plywood, fibre-and-pulp boards, and asbestos-cement boards. The large, rigid sheets are fastened directly to the frame of a building with nails, screws, or adhesives, or are mounted on furring (strips of wood nailed over the studs,joists, rafters, or masonry, which allow free circulation of air behind the interior wall). A significant advantage afforded by drywall construction is that it allows a builder to avoid the unnecessary delays attendant to the drying of wet plaster before other work can be started or before the on-site work required to achieve specific finishes may be completed. Wallboard is manufactured in both finished and unfinished forms, and finished wallboards may be faced with vinyl or other materials in a variety of permanent colors and textures so that they do not need to be painted when installed.
When employing drywall in construction, builders can easily cut the panels to any desired shape and size. However, workmen face a challenge in finishing drywall panels at an edge or corner. It is very difficult, if not impossible, to cut the edges of such panels with the precision, straightness, and smoothness that is required so that the abutted edges of adjoining panels form a straight corner that will afford an aesthetic finish. Additionally, cutting of the drywall panels exposes the soft, raw cores thereof, thus requiring some sort of covering to provide a finished appearance.
In light of the limitations of drywall tape, trim strips or corner beads are often utilized in effort to produce a seamless and aesthetically pleasing edge trim or intersection at the corners of drywall panels.
Such trim may take many different forms such as a flat strip, a corner bead having flanges diverging at any one of a number of different angles, or a J strip to cap the edge of a dry wall panel. For the purposes of this invention, the particular angular configuration is not critical, but use in conjunction with numerous different configurations presently in existence and that may be developed in the future is contemplated. Further examples of corner trims include beads with perpendicular flanges, corner trims with a rib formed at the juncture of the flanges, flanges angled at 135° to one another, those configured with somewhat of a Z shape, those with soft line corners, and those with offsets or other configurations traditionally used in the trade and known to those skilled in the art.
To enhance the finished appearance of construction finished drywall with such trim, efforts have been made to cover a hard structural core with an exterior covering of paper or paper-like material to enhance the finished appearance. It is recognized that by covering a plastic or metal core with paper, the paper will serve to cooperate with the covering on adjacent drywall panels to, when covered with a joint compound, afford a continuous smooth appearance from such panels and over the resultant trimmed joint. The compound may be sanded down and feathered in effort to provide a continuous smooth surface.
A disadvantage arising from the use of such paper covered trim cores is that during the sanding process, the workman sometimes sands through such compound and into the paper layer. This sanding tends to scuff up the fiber in the paper layer leaving somewhat of a scuffed or abraded surface, oftentimes with frayed fiber ends. This results in a discontinuous and unattractive surface. Efforts to solve this problem have led to the development of various different trims and corner beads that incorporate a protective layer constructed of either a strengthening compound or paper impregnated at the outer surface.
While these advancements may act to provide some strengthening to the covering paper, they do not adequately address the problem raised by sanding through the layer of material treated by the strengthening compound or the problems posed by separation of the paper from the core element with shrinkage of the paper cover. This issue becomes especially evident when trim strips or beads are subjected to high temperatures above about 100° F., as during storage in sheds, during transportation, or after prolonged exposure to various environmental conditions. In such instances, the paper covering will often shrink and bubble up on the core or pull away from it, particularly in any areas of any irregularity such as adjacent any shoulder or rib formed in such core. This bubbling and separation of the paper covering is often detected only at the construction site after the product has been transported and stored for preparation of the drywall phase of the construction project. Consequently, the onsite workman oftentimes reject and discard any strips with such deteriorated trim resulting in significant waste of both product and time.
Consequently, there exists a need for a durable, affordable, and aesthetically pleasing corner bead device having a paper covering not susceptible to shrinkage or rupturing at elevated temperatures or after prolonged exposure to the environment.